lining up of HD lathe

[gbircumshaw]

Hi,
i am having problems gitting the alignment right from center to center on a HD lathe which i operate. the tailstock has since been lifted from the lathe bed, and i am wondering if there is any kind of equipment to make the alignment process any easier/quicker.
A previous job which was machined was 3mm oval on the 2500m dia.
any ideas plz

 

[Timelord]

Not sure what you mean by a HD lathe and did you really mean a 2500 meter diameter? Typically a misaligned tailstock will cut a taper on a long cut. Not sure how it would cut an oval, probably not from a misaligned tailstock. For a taper, make a long cut and measure the taper, then move the tailstock 1/2 the difference and check with another long cut, repeat if required until the taper is gone.

Timelord

 

[unclesyd]

The easiest way to align any machine tool is with a laser. There are many firm that will come in and in a day align all you machine tools.
We use equipment from Hamar for all of our machine tool alignment.

http://www.hamarlaser.com/index.html

 

[GregLocock]

And if you want to diy, get a gunsight laser, a mirror and some card.

Mount the gunsight laser in the 4 jaw chuck, and the mirror on the tailstock.

Fiddle with the alignment of each until the reflected dot is centred on the laser, and the dot at the tailstock is centred on the tailstocks axis.

You'll need to be able to spin the mirror to check that it is square to the tailstock's bore.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Pud]

Whatever happened to autocollimaters and optical squares/hexagons?

Oh well, must be older than Methusala!

Although, out of round is not alignment problem as previously stated - more likely headstock bearings/crosslide play..

Cheers

Harry

 

[MintJulep]

Or whip from out-of-balance stock.

 

[Compositepro]

I think Timelord gave the best advice. Laser dots are not infinitely small or round. Electronic detectors are required to get any precision. These instruments are costly and require training. Adjusting tailstocks to center is something that is commonly done since lathes were invented. And this is not simply a one time adjustment on installation. Tapers are part of what lathes are for. After a taper job the tail stock must be recentered.

Adju

 

[GregLocock]

You are absolutely right, for a precision lathe a gunsight laser is not accurate enough, by several orders of magnitude. Sorry about that

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[ajack1]

For a cheap Heath Robinson approach just get a ground bar with a centre drilled in each end, turn a dead centre in the jaws and put a live centre in the tailstock and clock the bar and adjust to suit.

On a lathe of any age the bed will have worn more in areas of high use so unless you want to do this for “every job” a compromise has to be struck, or a very costly rebuild.

Having said that I agree with others this is not likely to cause a 3mm oval.